Wonder in awe at the incredible intricacy of the human brain. The origins of the human brain start with a single cell within two weeks after conception. From a single differentiated cell, a complex orchestration of events occurs that is driven primarily by genes but is also influenced by environmental factors. It's astounding, given the complexities inherent in the developing brain, that this process typically leads to optimal brain function. Every brain, like every individual, is unique. Even identical twins, who share the same genetic code, are not completely identical, as many parents of identical twins can attest.

The Section on Social and Cognitive Developmental Neuroscience at the National Institute of Mental Health (NIMH) is devoted to better understanding not only individual differences that take place during brain development, but also different facets or abnormalities in individual development that can result in neurodevelopmental disorders, such as autism spectrum disorder and attention-deficit/hyperactivity disorder (ADHD).

The Section aims to better understand individual differences in youth with mental health disorders, including the interplay between genes, environment, and stochastic processes. By better understanding the factors that can influence different arrays of symptoms, we hope to shed light on the underlying mechanisms of mental disorders. While heterogeneity in neurodevelopmental disorders often creates challenges in understanding the underlying neurobiology, this heterogeneity is also a gift, making us all unique.